Catheters may be located in various venous locations and cavities throughout the body of a patient for introduction of fluids to a body or removal of fluids from the body. Such catheterization may be performed by using a single catheter having multiple lumens. A typical example of a multiple lumen catheter is a dual lumen catheter assembly in which one lumen introduces fluid and the other lumen removes fluid. Catheterization may also be performed by using multiple single-lumen catheters, such as TESIO® catheters sold by Medical Components, Inc. of Harleysville, Pa.
Each catheter lumen is typically connected to a distal end of an extension tube via a hub permanently secured to the catheter and the distal ends of the extension tubes. Each extension tube has a standard connector, such as a luer fitting, at its proximal end for connection to a medical device, such as a hemodialysis machine. A clamp, such as a Halkey Roberts clamp, is typically disposed over the extension tube. The clamp restricts fluid flow through the extension tube by compressing and closing the extension tube between a pair of clamp jaws. For long term catheterization, the clamp must be opened and closed numerous times, which may lead to a failure of the extension tube and blood loss from the catheter.
Clamps of the basic Halkey Roberts type are well-known, and are disclosed in various patents such as U.S. Pat. Nos. 3,942,228; 4,560,378; 4,588,160; 4,589,626; 5,035,399; 5,203,056; and 6,089,527. Structurally, such a clamp is a one-piece plastic member defined more or less by a skeletal framework and having two transverse end walls with apertures therethrough through which the tubing extends, whereby the clamp self-retains on the tubing even in the unlatched or open position. A latch arm extends from one end wall toward the other and includes a latching structure, and the other end wall includes a catch engageable with the latching structure. The latch arm and an opposing wall to the latch arm include tubing engaging surfaces, or clamp jaws, that engage and compress the tubing when the latch arm is in the latched position, which occludes the tubing to shut off fluid flow through the tubing until the clamp is released.
The end wall of the clamp thus described extends to a free end that is exposed and thus may become easily snagged by foreign objects such as clothing or wires or the like, resulting in unintentional and undesirable delatching and unclamping from the tubing. Also, the tubing's resistance to being clamped exerts force in a direction tending to pry the latch arm to overcome the catch and thus open inadvertently, and the skeletal end wall that is remote from the latching arrangement becomes stressed and weakened over repeated clamping/unclamping cycles, eventually leading to failure and breakage in many cases. Commercially available Halkey Roberts clamps commonly extend along the tubing for a length of just under one inch (254 mm).
In above-cited U.S. Pat. Nos. 4,588,160; 4,589,626; and 4,673,161, the clamping jaws are axially offset. In another patent, U.S. Pat. No. 4,623,102, a clamp is disposed transversely and provides a pair of planar clamping surfaces to grip the tube. In both U.S. Pat. Nos. 4,589,626 and 4,623,102, the clamp has two or more clamping positions, enabling either selective occlusion or capability of utility with tubing of different diameters.
It would be desirable to provide a clamp that is more resistant to delatching, that is more durable and that extends substantially less than one inch along the tubing.